| abstract |
The piezoelectric element of the present invention has a substrate, a lower electrode layer, a piezoelectric layer, and an upper electrode layer sequentially formed on the substrate. The linear thermal expansion coefficient of the substrate is made larger than the linear thermal expansion coefficient of the piezoelectric layer, and the piezoelectric layer is made into a polycrystal having in-plane stress in the compression direction. This realizes a piezoelectric element having a high orientation in the polarization axis direction, a high proportionality of the displacement amount with respect to the applied voltage, and a large absolute value of the displacement amount. |